Slide 1

QF1 vibration status A.Jeremie A.Jeremie, N.Geffroy, drawings by Araki-san Slide 2 A.JeremieATF2 Workshop Annecy March 18, 20142 14 GM sensors have been installed in EXT and FD -Measurements are available -BPM and ground motion data have been taken in parallel. -Setup works very well. Slide 3 QD0 relative to ground A.JeremieATF2 Workshop Annecy March 18, 20143 Transfer Function flat below the resonance Vertical resonance at 68 Hz Horizontal resonance at 18 Hz Vertical Relative displacement at 1Hz is 4 nm 2008 68 Hz 18 Hz 4 nm 28 nm ! Benoit used green for vertical Slide 4 QF1 relative to ground A.JeremieATF2 Workshop Annecy March 18, 20144 Coupling between vertical and horiz. vibrations Vertical resonance at 31 Hz Horizontal resonance at 8 Hz Vertical Relative displacement at 1Hz is 21 nm 2008 31 Hz 8 Hz 21 nm 290 nm Slide 5 Displacement relative to ground 2013 (2008) Shintake Monitor QD0QF1 Main resonance (vertical)50 Hz (50 Hz)68 Hz (66 Hz)31 Hz (66 Hz) Vertical displacement6,8 nm (4 nm)4 nm (3 nm)21 nm (4 nm) Main resonance (perpendicular) 15 Hz (21 Hz) Displacement perpendicular to the beam Not doneNot possible: hole on top QD0 100 nm (30 nm) Main resonance (parallel)50 Hz (50 Hz)18Hz (17 Hz)8 Hz (19 Hz) Displacement Parallel to the beam 13 nm (11 nm)28 nm (25 nm)290 nm (21 nm) A.Jeremie5ATF2 Workshop Annecy March 18, 2014 Slide 6 Larger relative displacement QF1 to Shintake monitor has consequences on the beam growth A.JeremieATF2 Workshop Annecy March 18, 20146 Presented by Okugi-san (Sept 27, 2013) QD0FF QF1FF Slide 7 Where does the difference come from? There are two main differences between the old QF1 set-up and the new one and both can contribute to the new vibration behaviour: the bigger mass of QF1 ( x3 from 450kg to 1184kg) the new support Most probably from the big mass, but it would be better to exclude contribution from support A.JeremieATF2 Workshop Annecy March 18, 20147 Old QF1New QF1 Slide 8 A.JeremieATF2 Workshop Annecy March 18, 20148 Plate B Plate A Araki-san Slide 9 A.JeremieATF2 Workshop Annecy March 18, 20149 Plate B Plate A Araki-san Slide 10 How can we separate contributions? Easiest is to make a measurement to identify the source of the peaks. Redo the vibration measurements around FD but by separating QF1 from support: one could lower the plate B down to plate A and fix it (removing the M20 screws and corner blocks). That way, the vibration measurement would only measure QF1 on movers without any contribution from the support. By comparing measurements with/without support one could start identifying the peaks in the spectrum A.JeremieATF2 Workshop Annecy March 18, 201410 Slide 11 A.JeremieATF2 Workshop Annecy March 18, 201411 Plate A Plate B Slide 12 Possible plan When beam is stopped (between end of June and beginning of October): lower the plate B until it is fixed on plate A. Does one have to lift QF1 or can it be done easily just with the M20 screws? Do the vibration measurement with 2 sensors (on the table and on QF1) Put back plate B in place and realign QF1 before beam in October. A.JeremieATF2 Workshop Annecy March 18, 201412